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Sunday, September 7, 2008

Pollution

Industrial solid waste are also sorted out as biodegradable and non degradable wastes bio degradable wastes are generated by cotton mills food processing units and paper mills and textile factoriesNon biodegradable wastes are generated by thermal power plants which produce fly ash integrated iron and steel plants which produce blast furnace slag and stell melting slag industries manufacturing aluminum zinc and copper produce gypsum hazardous wastes such as immflammables composite explosives or highly reactive substances are produced by industries dealing in metals chemicals dues etcThe disposal of non degradable industrial wastes if not done by a proper and suitable method may cause serious thereat to the environment new innovation have led to different used of waste material nowadays fly ash and slag from the steel industry are utilized by the cement industry large quantities of toxic wastes are usually destroyed by controlled incineration whereas small quantities are burnt along with factory garbage in open bins moreover solid wastes if not managed effectively affect the components of the environment

STARTEGIES T O CONTROL ENVIRONMENTAL POLLUTIONAfter studying air water soil and industrial waste pollution in this unit by now you must have started feeling the need of controlling environmental pollutionWaste managementSolid waste is not he only waste which u see your house hold garbage box besides house hold discard there are medical agricultural ,industrial and mining wastes the improper disposal of wastes is one of the major causes of environmental degradation therefore the management of wastes is of utmost importanceCOLLECTION AND DISPOSALDomestic wastes are collected in small bins which are then transferred to community bins by private or municipal workers .from this small bins these are collected and carried to the disposal box

GREEN CHEMISTRY

It is well known fact that self sufficiency in good has been achieved in India since late 20 century by using fertilizes and pesticides and exploring improved methods of farming good quality seeds irrigation etc but over exploitation of soil and excessive used of fertilizers and pesticides have resulted in the deterioration of soil water and airThe solution of this problem does not lie in the stopping the process of development that has been set in but to discover methods which would help in the reduction of deterioration of the environment green chemistry is a way of thinking and is about utilizing the existing knowledge and principles of chemistry and other science to reduce the adverse impact on environment. that a would bring about minimum pollution or deterioration to the environment .The bye products generated during a process if not used gainfully add to the environmental pollution such process not only environmental unfriendly but also cost – ineffective the waste generation and its disposal both are economically un sound utilization of existing knowledge base for reducing the chemical hazards along with the developmental activities is the foundation of green chemistryPosted by josh at 8:52 PM 0 commentspottutionENVIRONMENTAL POLLUTIONEnvironmental pollution is the effect of undesirable and changes in our surrounding that have harmful effects on plants animals and human beings a substance which causes pollution is knows as pollutant pollutants can be solids liquids or gaseous substances present in greater concentration than in natural abundance and are produced due to human activates or due to natural happenings

ATMOSPHERIC POLLUTIONThe atmosphere that surrounds the earth is not of the same thickness at all heights there are concentric layers of air and regions and each layer has different densityThe lowest region of atmosphere in which the human beings along with other organisms live is called the troposphere it extends up to the height of 10 and 50 kilometer troposphere is a turbulent dusty zone containing air much water vapour and clouds. this is the region of strong air movement and cloud formation the stratosphere on the other hand contains dinitrogen dioxygen ozone and little water vapour

TROPOSHERIC POLLUTIONTroposphere pollution occurs due to the presence of undesirable solid or gaseous particles in the air the following are the major gaseous and particulate pollutants present in the troposphere .Gaseous air pollutants there are oxides of sulphur nitrogen and carbon hydrogen sulphide nitrogen ozone and other oxidantsParticulate pollutants these are dust mist fumes smoke etc

Gaseous air pollutantsOxides of sulphurOxides of sulphur containing fossil fuel is burnt in air the most common species sulphur dioxide is a gas that is poisonous to both animals and plants it has been reported that even a low concentration of sulphur dioxide Causes asthma bronchitis .sulphur dioxide causes irritation to the eyes resulting in tears and redness high concentration of son3 leads to stiffness to flower buds which eventually fall off from plants unanalyzed oxidation of sulphur dioxide is slow however the presence of particulate matter in polluted air catalyses the oxidation of sulphur dioxide to sulphur trioxide

Oxides of nitrogenDinitrogen and dioxygen are the main constituents of air these gases do not react with each other at a normal temperature at high altitudes when lighting strikes they combine to form oxides of nitrogen no is oxidized to nitrate ion Which is washed into soil where it serves as a fertilizer in an automobile engine when fossil fuel is burnt dinitrogen and dioxygen combine to yield significant quantities of nitric oxide and nitrogen dioxide

Oxides of carbonCarbon monoxideCarbon monoxide is one of the most serious air pollutants it is a colourless gas highly poisonous to living beings because of its ability to block the delivery of oxygen to the organs and tissues it is produced as a result of incomplete combustion of coal firewood petrol the number of vehicles has been increasing over the rears all over the world many vehicles are poorly maintained and several have inadequate pollution control equipments resulting in the release of greater amount of carbon monoxideCarbon dioxideCarbon dioxide is released into the atmosphere by respiration burning of fossil fuels

for energy and by decomposition of lime stone carbon dioxide gas is confined to troposphere onlyGlobal warming and green house effectAbout 75%pf the solar energy reaching the earth is absorbed by the earth surface which increase its temperature the rest of the hear radiates back to the atmosphere some of the hear is trapped by gases such as carbon dioxide methane ozone chlorofluorocarbon compounds and water vapor in the atmosphere thus they add to the heating of the atmosphere this cause global warming

Stratospheric pollutionFormation and breakdown of ozone The upper stratosphere consists of considerable amount o ozone which protects us from the harmful ultraviolet radiations coming from the sum. These radiations cause skin cancer in humans there fore it is important to maintain the ozone shield .Ozone in the stratosphere is a product of uv radiations acting on dioxygen molecules the uv radiations split apart molecular oxygen into free oxygen atoms these oxygen atoms combine with the molecular oxygen to form ozone is thermodynamically unstable and decomposes to molecular oxygen thus a dynamic equilibrium exists between the production and decomposition of ozone molecules in recent years there have been reports of the depletion of this protective ozone layer because of the presence of certain chemicals in the stratosphere .The ozone holeIn atmospheric scientists working in Antarctica reported about depletion of ozone layer commonly knows as ozone hole over the south pole nitrogen dioxide and methane react with chlorine monoxide and chlorine atoms forming chlorine sinks preventing much ozone depletion where as in winter special type of clouds called polar stratospheric clouds are formed over Antarctica these polar stratospheric clouds provide surface on which chlorine nitrate formed gets hydrolyzed to form hypochlorous acid. It also reacts with HCl produced as per reaction to give molecular chlorine.When sunlight returns to the Antarctica in the spring, the sun’s warmth breaks up the clouds and HOCl and Cl2 are photolysis by sunlight. The chlorine radicals thus formed, initiate the chain reaction for ozone depletion.Effects of Depletion of the Ozone LayerWith the depletion of ozone layer, more UV radiation filters into troposphere. UV radiations lead to ageing of skin, cataract, sunburn , skin cancer, killing of many phytoplankton’s, damage to fish productivity etc.

WATER POLLUTION

Water is essential for life without water there would be no life we usually as granted for it purity but we must ensure the quality of water. Pollution of water originates from human activities. Easily identified sources of water pollution is called point source. E.g., municipal and industrial discharge pipes where pollutants enter the water-source. on point sources of pollution are those where a source of pollution cannot be easily identified, e.g., agricultural run off, acid rain, storm-water drainage etc.

Causes of Water Pollution1) Pathogens: The most serious water pollutants are the disease causing agents called pathogens. Pathogens include bacteria and other organisms that enter water from domestic sewage and animal excreta. Human excreta contain bacteria such as Escherichia coli and Streptococcus faecalis which cause gastro intestinal disease2) Organic wastes : the other major water pollutant is organic matter such as leaves grass trash etc they pollute water as consequence of run off .excessive phytoplankton’s growth with in water is also a cause of water pollution these wastes are also biodegradable3) Chemical pollutants : as we know that water is an excellent solvent water soluble inorganic chemicals that include heavy metals such as cadmium mercury nickelEtc constituent an important class of pollutants as all these chemicals are dangerous to humans as our body can’t excrete them over the time it crosses the tolerance limit these metals then can damage kidneys central nervous system liver etc

ENVIRONMENTAL POLLUTIONEnvironmental pollution is the effect of undesirable and changes in our surrounding that have harmful effects on plants animals and human beings a substance which causes pollution is knows as pollutant pollutants can be solids liquids or gaseous substances present in greater concentration than in natural abundance and are produced due to human activates or due to natural happenings